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Epic Code LAB2111082 Glucose Tolerance, 1 hour test, 50 g (Gestational Diabetes Screen)

Important Note

This is a non-fasting test.

This test is recommended and only available as a screen for PREGNANT patients at 24-28 weeks gestation. The patient is given a 50 gram oral glucose load and blood is drawn one hour later.

For outpatient collection: Providers please instruct patient to arrive at least 90 minutes prior to the lab closing to ensure there is enough time to complete the test. LINK: List of Laboratory Locations and Hours

Test Name Alias

Glucose 1 hr Post 50 g |Glucose Tolerance |Glucose | GTT | OGTT | 8040 | 1230100719

Interface Order Alias

10146

Ordering Instructions

This test is recommended and only available as a screen for PREGNANT PATIENTS at 24-28 weeks gestation.

 

For safety and accuracy of testing, patients are encouraged to have Oral Glucose Tolerance Tests (OGTT) performed at one of our Outpatient Service Centers.

 

GlucoCrushTM, the glucola drink used in Corewell Health Grand Rapids Laboratory does not contain gluten.

Specimen Requirements

Specimen Collection: Blood

 

Container(s): Gray Top (Potassium Oxalate and Sodium Fluoride)

  • Also acceptable: Light Green Top (Lithium Heparin Gel) OR 5.0 mL Gold Top (Serum Separator-SST Gel)
  • Minimum Volume to Collect: 1.0 mL
  • Neonate Volume to Collect: 0.5 mL
  • Capillary collect ok? Yes
  • Microtainer acceptable: Yes

Collection Instructions:

  • After collection, gently invert tube 8-10 times.
  • Gray top whole blood is preferred specimen type
  • If collecting green or gold top:
    • Specimen should be processed within 2 hours – See Processing Instructions.
    • Processed Specimen: Plasma or Serum
    • Centrifuge/Spin: Yes
    • Aliquot: Yes
    • Processing Instructions:
      • Gold Tube/Serum: Allow blood to clot for 30 minutes in a vertical position and centrifuge within 2 hours.
      • Green Tube/Plasma: Centrifuge after collection.
      • Minimum plasma/serum volume: 0.5 mL

Transport Temperature: Refrigerated

 

Lab Central Instructions:

  • Centrifuge Gray-top tubes before delivery to the appropriate testing station.

Specimen Stability

Ambient: 8 hours

Refrigerate: 72 hours

Frozen: aliquot plasma/serum for longer storage

Laboratory Retention: 72 hours

Test Frequency

Available daily, usual TAT 1 day.

Reference Range

Female
65 – 135 mg/dL

Performing Department

Chemistry

Performing Department Laboratory Location

Corewell Health Reference Laboratory, Grand Rapids, MI
Corewell Health Big Rapids Laboratory, Big Rapids, MI
Corewell Health Blodgett Laboratory, Grand Rapids, MI
Corewell Health Gerber Laboratory, Fremont, MI
Corewell Health Greenville Laboratory, Greenville, MI
Corewell Health Ludington Laboratory, Ludington, MI
Corewell Health Pennock Laboratory, Hastings, MI
Corewell Health Reed City Laboratory, Reed City, MI
Corewell Health Zeeland Laboratory, Zeeland, MI

 

CHS

Corewell Health Lakeland St. Joseph Laboratory, St. Joseph, MI

Methodology

Enzymatic

CPT

82950, 82950

CDM Code

3018295001, 3018295001

Epic Test ID

1230100719

LOINC

Glucose 1Hr PP: 1504-0

Reviewed Date

3/7/2024

Updated Date

5/13/2025 - CHS info added

Orderable Regions

Southwest; West